This invention relates generally to verifying that manufacturing processes are being performed acceptably during manufacturing, and, more particularly to the ability to perform this verification, and retain documentation of this verification, throughout large and complex envelopes.
Manufacturing errors are expensive. An error in manufacturing results in costs relating to raw materials, machine time, resolution time, and rework or scrap disposal.
The cost of a manufacturing error is lowest when the error is detected and corrected at the earliest possible time in the process. Each process which occurs after a manufacturing error has occurred adds costs to the product. The flawed product will eventually cause a manufacturing disruption or become scrap. A dimensioning error which is not detected when the dimension is created can allow the repeated production of parts which will not function properly.
It has been said that quality cannot be “inspected into” parts. Quality is the result of each and every process occurring correctly. By monitoring dimensional quality “in process” (as the process is occurring) problems can be detected and resolved at the earliest possible time and at the lowest possible cost. The detection of developing problems, during process deterioration but before unacceptable processing occurs, lowers costs and improves the efficiency of a manufacturing system. Costs are reduced by resolving the problem before scrap is created or downstream disruptions occur.
There are many factors, which limit inspection during production. One limitation of inspection is related to the envelope, or size, of the inspection capability. High accuracy inspection envelopes are small. Large inspection envelopes tend to compromise accuracy. The quality of inspection is often inversely proportional to the time spent performing the inspection.
The complexity of the product being inspected is another factor, which affects the ease and accuracy of inspection. Simple shapes are easier to inspect with high precision. Complex shapes are more difficult to inspect with precision.
The same factors that affect inspection during production also affect inspection after production. Inspection after production facilitates preventive maintenance and can prevent catastrophic failures.
The High Resolution, High Accuracy Process Monitoring System described in U.S. Pat. No. 6,304,680 (issued on Oct. 16, 2001 to S. Blake et al.), herein incorporated by reference, captured images (only images) for analysis by aiming a camera through the optical aiming system of the laser projector.
In order to inspect large envelopes and complex surfaces, it is desirable to place the inspection data gathering device in close proximity to the region being inspected. It is also desirable to obtain an accurate determination of the location being inspected.
It is therefore an object of this invention to provide a method and system that enable the inspection of large envelopes and complex surfaces.
It is a further object of this invention to provide a method to enables the obtaining of accurate relative position information while utilizing a coarse positioning and aiming method, such as manual placement, for placing the inspection data gathering device.
It is still a further object of this invention to provide a method and system that enable the use of a variety of inspection sensors besides image capture sensors.